Stripped phillips screw on stator assembly....

[CoconutPete]

So I started installing my PMA tonight. All was going well until it came time to remove the stator assembly.

The instructions recommended using an impact, so that's what I did.

The first one was stubborn, but jjuuuuusst made it off before it morphed into a useless screw.

The second one moved, but stripped before it came loose. Tried vice grips - no luck. Tried a screw extractor... even bigger fail! Basically just drilled a conical hole in the screw.

Based on the other screw there's a decent length of rod back there without threads ... so I'm thinking maybe drill it and attack it once the stator assembly is off.

What does the wisdom of the board think?

 

[figure8]

Are you trying to salvage the stator or just want it off?

 

[650Skull]

If you have got to that point just get a decent sized drill bit and drill of the head, The shaft can be got off once the stater has been removed

 

[5twins]

Just because you have one of those hand held impacts doesn't exempt you from fuck-ups, lol. You have to use it properly. You can mess up screw heads quicker and more than with a hand held screwdriver if you don't. First, obviously, is using the right size Philips bit. That's pretty hard to FUBAR so we'll skip to the second thing. You have to plant that bit squarely and straight into the screw head. Then, and this is the secret, you have to rotate the impact in the direction you're trying to go and take up all the slack in the tool. You must do this BEFORE you hit it with the hammer. If you don't, well, bad things may happen (read post #1).

 

[fredintoon]

Hi Pete,
like they said, just drill the head off.
Be gentle with the stator, if it still works someone may be willing to swap you something for it.

 

[650Skull]

Of all the times advice has been given on getting a Impact driver this is the first time it has been explained "How To Use"

I won't use them any more because of their limited usability.

I use a Battery operated drill that has a clutch on the screw part. Set this low and use as a ratchet then increase the grade until the screw brakes loose. Have to use the ratchet part without the drill actually trying to undo the screw, this will vibrate and brake the rust or if the head is damaged, (even quite bad), can still get the screw out.

As 5Twins says the right sized bit is important and holding whatever your using, Square to the head/screw

 

[5twins]

Even though I've had and used these hand held impacts for many, many years, they can still fail me on occasion. That is usually because I failed to follow my own advise as outlined above.

 

[fredintoon]

Just had a thought; Pete's post said "Phillips screw" but Yamaha's cross point fasteners use the not-quite-the-same Japanese equivalent head.
If Pete used an actual Phillips drive bit when trying to remove the stator screws that could have been the last straw that made the screw head crater out.

 

[marp68]

Try using a left driven drillbit. If the screw is not extremely tight this will force it out. The drillbit starts to make a hole but when harder it starts to unscrew the bolt instead. Did this myself once. And don't forget to set the drill machine to drill left.

 

[kevski]

Just had a thought; Pete's post said "Phillips screw" but Yamaha's cross point fasteners use the not-quite-the-same Japanese equivalent head.
If Pete used an actual Phillips drive bit when trying to remove the stator screws that could have been the last straw that made the screw head crater out.

Absolutely right they use JiS Japanese industry standard, you can adapt phillips screw drivers by grinding a small amount of the tip off.

 

[gggGary]

Yes drill the head, and a set of LH bits is a good investment. IIRC the stator heads are #3 phillips. Tried to remove with a #2 bit? Yeah technically they are JIS and yes they are a slightly different shape, but seriously, I have NEVER had a problem using a quality brand #2 or #3 bit that was in decent shape. Philips bits and screw drivers DO wear out. I build a lot of stuff with drywall screws, probably use up 5 or 10 bits a year. As always, if a screw is being stubborn, STOP, reverse the impact, try tightening it a bit, then go back to loosening. Repeat this a couple of times if needed. On a PO buggered screw head; set the bit into the screw head with a couple hammer smacks, this helps reform the screw head Then use the impact wrench. Use rust buster though it's hard to get it where it needs to go on the stator. Yes with the head off there is plenty of shank to get that screw out.

 

[retiredgentleman]

I've always had good experience with manual impact tools. I bought a Sears Craftsman impact tool about 40 years ago. It came with 4 bits. One of the bits is a JIS bit, which fits just perfectly into motorcycle screws. They are a "must own" tool on these bikes.

However having said that, about a year ago, I converted my stator screws to bolts. I now use a 10 mm socket. As a matter of fact, I just removed my stator yesterday, to allow cleaning of the rotor slip rings, which I clean once a year. The bolt head just makes it so simple to use a torque wrench, which I set at 65 in/lbs, when I re-installed them.

 

[vr3506]

Most people didn't even hear about JIS screws....mostly they have a dot on there head

 

[CoconutPete]

Well... I poured a glass of Knob Creek and sat there and stared at it for a minute. Then it hit me like a ton of bricks. Dremel! I cut a line across it and got it out with a big flathead. Thanks for the suggestions.